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Note that those who were in the awake ECMO group also had a shorter course of mechanical ventilation after transplant surgery.

Extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation increased survival compared with mechanical ventilation in awake, spontaneously breathing patients, according to a retrospective study.

Survival at six months was 80% in those receiving "awake ECMO" compared with 50% in those who received mechanical ventilation (P=0.02) reported Marius M. Hoeper, MD, from Hannover Medical School in Hannover, Germany, and colleagues in the American Journal of Respiratory and Critical Care Medicine.

Those who were in the awake ECMO group also had a shorter course of mechanical ventilation after transplant surgery (P=0.04), the group said.

Mechanical ventilation is associated with poor outcomes as a bridge to transplant. As waiting times for lung transplantation increase, the researchers wanted to determine if ECMO in awake patients who were breathing without assistance could prove useful.

In this single-center, intention-to-treat analysis, the researchers reviewed the charts of 26 consecutive lung transplant candidates with terminal respiratory or cardiopulmonary failure. They received awake ECMO as a bridge to lung transplantation between August 2008 and March 2011.

The outcomes were compared with a historical control group of 34 patients treated with conventional mechanical ventilation as bridge to transplant between January 2006 and August 2008.

The duration of awake ECMO support and mechanical ventilation were comparable: A median nine days for awake ECMO versus median 15 days for mechanical ventilation (P= 0.25).

In the awake ECMO group, 23% of the patients, and 29% of patients in the mechanical ventilation group died before a donor organ was available (P=0.20).

The longest successful duration of awake ECMO support was 45 days. Of the 13 ECMO patients who were discharged from the hospital, all remained alive during the follow-up period (seven to 39 months).

The median ventilator time following the transplant operation for the awake ECMO cohort who survived to discharge was 14 days, and five could be extubated within the first 24 hours. In comparison, the mechanical ventilation patients who survived to be released from the hospital were on the ventilator longer (37 days, P=0.04); spent more time in the ICU (39 versus 18 day, P=0.07); and were discharged later from the hospital (67 versus 38 days, P=0.06).

Patients in the awake ECMO group did experience some complications: 31% required blood transfusions while 27% required secondary intubation and mechanical ventilation. Other complications in this cohort were massive hemoptysis/epistaxis, sepsis-like syndrome, and multi-organ failure and organ replacement therapy.

The authors stressed that "these events show that ECMO remains associated with serious, potentially fatal complications and should therefore be used only in experienced centers and only in patients in whom noninvasive treatment options have been exhausted."

Study limitations included the small number of patients at a single center. In addition, the analysis was done retrospectively using historical controls instead of a parallel group.

But the main benefit of the awake ECMO concept is the "avoidance of the complications and drawbacks associated with general anesthesia, intubation, and long-term ventilation," the authors pointed out.

"Our findings serve as proof-of-concept that 'awake ECMO' may be an effective feasible bridging strategy for patients with terminal respiratory diseases," they said, but cautioned that more research was necessary to improve the technique's safety and efficacy, and to tailor the various modalities of extracorporeal life support in different patient populations.

"Until more data is available, this strategy remains investigational and should not yet be considered standard of care," they wrote.

No disclosure or conflict of interest information was available.

The ECMO devices used were a Rotaflow centrifugal pump, a Biomedicus pump and and a Quadrox i Adult membrane oxygenator, all manufactured by MAQUET Cardiovascular of Fairfield, N.J.

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